Category

Research

In Research, Tracked Vehicles General, Tracked Vehicles Robots

Trench-Crossing Capability Analysis of a Reconfigurable Tracked Mobile Robot

Trench-Crossing Capability Analysis of a Reconfigurable Tracked Mobile Robot

Hei Mo, Shang Jianzhong, Luo Zirong, Wang Zhuo, Intelligent Robotics and Applications, 2010, pp.509-518.

In Machinery, Machinery with Belts/Chains/Cables, Research

Mock-up of a support structure of the ITER vacuum vessel

Mock-up of a support structure of the ITER vacuum vessel

H.J. Ahn, J.W. Sa, Y.K. Kim, Y.S. Hong, J.H. Choi, T.H. Kwon, J.S. Lee, K.H. Park, T.S. Kim, W.I. Ha, I.S. Choi, B.C. Kim, K.H. Hong, C.H. Choi, Fusion Engineering and Design, June 2009, Volume 84, Issues 2-6, pp 375-379.

Abstract

The ITER vacuum vessel support systems located in the lower level sustain loads in radial and vertical direction. The support system consists of various sub-components like a linkage system, a pot type bearing, a vertical rope, a toroidal constraint, and dampers. In order to examine performance of the mechanism of the system, a mock-up of the linkage system which is comparatively complicated has been manufactured. Various fabrication methods were studied through the mock-up fabrication, and also several tests have been done using the mock-up. Those include assembly study, stroke test, static load test and fatigue test. In the full stroke test, the functional mechanism of the support structure has been demonstrated. In the structural test, the strength of the all components is evaluated by measuring reaction and strain of each component. In order to investigate the effect of tolerances and the damage due to the tests, the performance tests were conducted before and after the static and fatigue tests. The backlash for each stage is found from measured displacement hysteresis. As results of those tests, the performance of the ITER vacuum vessel support structure as well as its structural integrity has been evaluated in this study.

How Multibody Dynamics Simulation Technology is Used

RecurDyn was used to test the design of a vacuum vessel support system. The reaction forces at rotational joints, displacements, and rotation angles were obtained from the model. This information could be used to make intelligent design decisions regarding the geometry and materials used in the system.

Get This Paper

Related Case Studies
In Biomechanics, Multibody Dynamics, Research

Simulation of extension, radial and ulnar deviation of the wrist with a rigid body spring model

Simulation of extension, radial and ulnar deviation of the wrist with a rigid body spring model

S. Fischli, R.W. Sellens, M. Beek, Dr. Pichora, Journal of Biomechanics, Kingston, June 2009, Volume 42, Issue 9, pp 1363-1366.

Abstract

A novel computational model of the wrist that predicts carpal bone motion was developed in order to investigate the complex kinematics of the human wrist. This rigid body spring model (RBSM) of the wrist was built using surface models of the eight carpal bones, the bases of the five metacarpal bones, and the distal parts of the ulna and radius, all obtained from computed tomography (CT) scans of a cadaver upper limb. Elastic contact conditions between the rigid bodies modeled he influence of the cartilage layers, and ligamentous structures were constructed using nonlinear, tension-only spring elements. Motion of the wrist was simulated by applying forces to the tendons of the five main wrist muscles modeled. Three wrist motions were simulated: extension, ulnar deviation and radial deviation. The model was tested and tuned by comparing the simulated displacement and orientation of the carpal bones with previously obtained CT-scans of the same cadaver arm in deviated (451 ulnar and 151 radial), and extended (571) wrist positions. Simulation results for the scaphoid, lunate, capitate, hamate and tri quetrum are presented here and provide credible prediction of carpal bone movement. These are the first reported results of such a model. They indicate promise that this model will assist in future wrist kinematics investigations. However, further optimization and validation are required to define and guarantee the validity of results.

How Multibody Dynamics Simulation Technology is Used

The high performance and robust contact modeling capabilities in RecurDyn are needed to simulate the complex interactions of bones in the wrist during the transition to various postures.

Get This Paper

Related Case Studies

In Nonlinear Dynamic System Theory, Research

A multibody-based dynamic simulation method for electrostatic actuators

A multibody-based dynamic simulation method for electrostatic actuators

Sangkyu Lee, Jinam Kim, Wonkyu Moon, Jinhwan Choi, Ilhan Park, Daesung Bae, Nonlinear Dynamics, October 2008, Volume 54, Issue 1, pp 53-68.

  • Abstract

    A numerical simulation method is developed to analyze the dynamic responses of electrostatic actuators, which are electromechanically-coupled systems. The developed method can be used to determine the dynamic responses of cantilever-type switches, which are an example of typical MEMS (Micro-Electro-Mechanical System) devices driven by an electrostatic force. We propose the approach that adopts a point charge to deal with electric field effects between electrodes. This approach may be considered as a lumped parameter model for the electrostatic interactions. An advantage of this model may be the easy incorporation of the electrostatic effects between electrodes into a multibody dynamics analysis algorithm. The resulting equations contain the variables for position, velocity, and electric charge to describe the motion of the masses and the charges on the electrodes in a system. By solving these equations simultaneously, the dynamic response of an electrostatically-driven system can be correctly simulated. In order to realize this approach, we implement the procedures into RecurDyn, the multibody dynamics software developed by the authors. The developed numerical simulation tool was evaluated by applying it to cantilever-type electrostatic switches in many different driving conditions. The results suggest that the developed tool may be useful for predicting behaviors of electrostatic actuators in testing as well as in design.

    How Multibody Dynamics Simulation Technology is Used

    This paper proposes a method to simulate the dynamic behaviors of structures driven by electrostatic forces. This approach provides dynamic simulation results that describe the effects of large deformations of a structure and the electromechanical coupling inside a system. RecurDyn’s FFlex module allows finite element bodies to be analyzed during multibody dynamics simulations.

    Get This Paper

    Related Case Studies

In Off-Road Material Handling, Research

Reduction of PTO rattle noise of an agricultural tractor using an anti-backlash gear

Reduction of PTO rattle noise of an agricultural tractor using an anti-backlash gear

S.B. Shim, Y.J. Park, K.U. Kim, Biosystems Engineering, 2008, Volume 100, Issue 3, pp. 346-354.

  •  Abstract

    An anti-backlash gear was developed and tested as a PTO rattle noise reducer for a direct-engine PTO driveline of agricultural tractors. Models of the anti-backlash gear and its driving gear were developed and used to simulate the relative angular displacement between them when idling. Computer simulations were also conducted to determine the minimum initial load of the anti-backlash gear for zero relative angular displacement. Performance simulation of the anti-backlash gear with different spring stiffness and initial deflections indicated that the PTO rattle noise by the impact could be eliminated by zero relative angular displacement and that rattle noise could be further decreased by increasing spring stiffness. In experiments the anti-backlash gear reduced the rattle noise by 11.4–16.9 dBA depending on the spring stiffness with zero relative angular displacement. A relationship between the stiffness and initial deflection of the spring is proposed for zero relative angular displacement. It is concluded that anti-backlash gear can reduce effectively the PTO rattle noise of the direct-engine PTO driveline of agricultural tractors when idling.

    How Multibody Dynamics Simulation Technology is Used

    RecurDyn was used to evaluate the design of an anti-backlash gear to reduce noise in the PTO gearbox of a direct-engine PTO driveline for an agricultural tractor. The simulated results matched well with measured results. The design of the anti-backlash gear could be tested and refined in an efficient and cost-effective way using RecurDyn.

    Get This Paper

    Related Case Studies

In RecurDyn in Education, Research

3D Education System of DC Motor Drive using RecurDyn and CoLink

3D Education System of DC Motor Drive using RecurDyn and CoLink

H.S. Mok, lH. LEE, G.H. CHOE, S.H KIM, DJ. YUN, ICPE 2007 Proceedings, October 2007, pp.119-121.